Intestinal Obstruction — MCQs
Assertion: Crohn's disease only affects the colon. Reason: Crohn's disease typically involves full-thickness inflammation of the bowel wall.
A surgeon examined the case of hernia. Forcefully reduces the sac in abdominal cavity, without actually pushing back the contents. Identify type of hernia with the image given.
All are features of congenital megacolon except:
What is the most common cause of intestinal obstruction?
String sign of Kantor is seen in:
Which of the following is the best combination of clinical features of intestinal obstruction?
Investigation of choice to diagnose hypertrophic pyloric stenosis in infants is
Which of the following features is used to identify the colon on an X-ray?
Treatment of choice for a stab injury to the caecum is
Most common cause of acute intestinal obstruction in children is
Intestinal Obstruction Indian Medical PG Practice Questions and MCQs
Question 1: Assertion: Crohn's disease only affects the colon. Reason: Crohn's disease typically involves full-thickness inflammation of the bowel wall.
- A. Assertion is false, Reason is true (Correct Answer)
- B. Both Assertion and Reason are true, but Reason does not explain Assertion
- C. Both Assertion and Reason are true, and Reason explains Assertion
- D. Both Assertion and Reason are false
Explanation: ***Assertion is false, Reason is true*** - The assertion is false because **Crohn's disease** can affect **any part of the gastrointestinal tract** from the mouth to the anus, not just the colon [1]. - The reason is true; Crohn's disease is characterized by **transmural inflammation**, meaning it involves all layers of the bowel wall. *Both Assertion and Reason are true, but Reason does not explain Assertion* - This option is incorrect because the **assertion itself is false**, as Crohn's disease can affect any part of the GI tract, not just the colon [1]. - While the reason is true regarding transmural inflammation, the premise of the assertion is flawed, making the relationship between the two irrelevant. *Both Assertion and Reason are true, and Reason explains Assertion* - This option is incorrect because the **assertion is false**; Crohn's disease is not limited to the colon. - Therefore, the reason, though true, cannot explain a false assertion. *Both Assertion and Reason are false* - This option is incorrect because the **reason is true**; Crohn's disease is indeed characterized by **full-thickness (transmural) inflammation** of the bowel wall. - Only the assertion is false.
Question 2: A surgeon examined the case of hernia. Forcefully reduces the sac in abdominal cavity, without actually pushing back the contents. Identify type of hernia with the image given.
- A. Sliding hernia
- B. Incarcerated hernia
- C. Maydl's hernia
- D. Reduction en masse (Correct Answer)
Explanation: ***Reduction en masse*** - **Reduction en masse** is a dangerous complication that occurs during attempted hernia reduction where the entire hernia sac, along with its incarcerated contents, is pushed back into the abdominal cavity. - The key feature is that **the contents remain trapped within the sac** after reduction, creating a false sense of successful reduction. - The scenario explicitly describes this: "forcefully reduces the sac... without actually pushing back the contents" - this is the textbook definition of reduction en masse. - This complication is dangerous because the incarcerated/strangulated bowel remains undetected inside the abdomen, potentially leading to **peritonitis and bowel necrosis**. - The hernia defect appears reduced externally, but the obstruction persists internally. *Incarcerated hernia* - An **incarcerated hernia** is the state where hernia contents are trapped and cannot be reduced back into the abdominal cavity. - This represents the **pre-existing condition** before the forceful reduction attempt was made. - While incarceration may have been present initially, the question asks about the outcome after the surgeon "forcefully reduces the sac" - this action creates a reduction en masse. *Sliding hernia* - A **sliding hernia** involves a retroperitoneal organ (colon, bladder, ovary) forming part of the hernia sac wall itself. - This is a structural variant unrelated to the reduction complication described in the scenario. *Maydl's hernia* - **Maydl's hernia** (W-hernia or retrograde strangulation) involves a loop of bowel where both ends remain in the abdomen while the intermediate segment is trapped in the hernia sac. - The strangulated segment is the intra-abdominal portion, not the part in the sac. - This is a specific type of hernia content configuration, not related to the reduction complication described.
Question 3: All are features of congenital megacolon except:
- A. Pseudodiarrhoea
- B. Tight anal ring
- C. Large bulky stools (Correct Answer)
- D. Failure to thrive
Explanation: ***Large bulky stools*** - Patients with **congenital megacolon** (Hirschsprung disease) typically have difficulty passing stool, leading to small, pellet-like stools or significant constipation, not large bulky stools. - The absence of **ganglion cells** in the affected segment prevents proper relaxation and propulsion, resulting in stool retention and a narrow, spastic segment. *Pseudodiarrhoea* - **Pseudodiarrhoea** can occur in congenital megacolon when liquid stool bypasses the impaction, leading to overflow incontinence. - This symptom is often mistaken for true diarrhea but is characteristic of severe constipation. *Tight anal ring* - A **tight anal ring** on digital rectal examination is a classic finding in Hirschsprung disease due to the spastic, aganglionic segment extending down to the internal anal sphincter. - This spasticity prevents normal relaxation of the internal anal sphincter. *Failure to thrive* - **Failure to thrive** is a common complication of congenital megacolon due to chronic constipation, poor nutrient absorption secondary to bowel stasis, and recurrent enterocolitis. - Chronic poor feeding and malabsorption contribute to inadequate weight gain and growth.
Question 4: What is the most common cause of intestinal obstruction?
- A. Ileocaecal tuberculosis
- B. Carcinoma colon
- C. Intussusception
- D. Adhesions (Correct Answer)
Explanation: ***Adhesions*** - **Post-surgical adhesions** are by far the leading cause of **small bowel obstruction** in adults, accounting for approximately 60-80% of cases. - They form as fibrous bands between tissue surfaces after surgery, which can later constrict or twist the bowel. *Ileocaecal tuberculosis* - While it can cause intestinal obstruction due to **stricture formation** and inflammation, it is a much rarer cause, particularly in developed countries. - This condition is more common in immunocompromised individuals or endemic areas. *Carcinoma colon* - **Colorectal cancer** is a common cause of **large bowel obstruction**, but it is less frequent as a cause of overall intestinal obstruction compared to adhesions. - The obstruction typically develops gradually as the tumor grows and narrows the bowel lumen. *Intussusception* - This is a more common cause of intestinal obstruction in **infants and young children**, where one part of the intestine telescopes into another. - In adults, it is a relatively rare cause of obstruction and is often associated with a **lead point** such as a tumor or polyp.
Question 5: String sign of Kantor is seen in:
- A. Crohn's disease (Correct Answer)
- B. Ulcerative colitis
- C. Typhoid colitis
- D. Colorectal cancer
Explanation: ***Crohn's disease*** - The **string sign of Kantor** is a classic radiographic finding in advanced Crohn's disease, particularly affecting the **terminal ileum**. - It refers to the appearance of a thin, continuous linear shadow of barium representing a severely narrowed, rigid, and stenosed lumen due to chronic inflammation and fibrosis. *Ulcerative colitis* - Ulcerative colitis primarily affects the **colon** and rectum, causing diffuse mucosal inflammation. - Common radiographic findings include **loss of haustrations** (lead pipe appearance) and **pseudopolyps**, not the string sign. *Typhoid colitis* - Typhoid colitis is a rare manifestation of **typhoid fever** (caused by *Salmonella Typhi*) that involves inflammation of the colon. - This condition presents with features of acute colitis, but not the chronic inflammatory changes or strictures leading to a string sign. *Colorectal cancer* - Colorectal cancer typically presents as a **mass lesion** or an **apple-core stricture** on barium studies, representing an obstructing tumor. - While it can cause luminal narrowing, it does not typically produce the diffuse, long-segment "string sign" characteristic of Crohn's disease.
Question 6: Which of the following is the best combination of clinical features of intestinal obstruction?
- A. Vomiting
- B. Fluid level in X-ray > 4
- C. Abdominal distension and vomiting (Correct Answer)
- D. Abdominal distension
Explanation: ***Abdominal distension and vomiting*** - This combination represents **two of the cardinal clinical features** of intestinal obstruction from the classic tetrad (pain, vomiting, distension, constipation). - **Abdominal distension** occurs due to accumulation of gas and fluid proximal to the obstruction. - **Vomiting** occurs as the body attempts to expel contents that cannot pass through the blocked intestine. - The **combination** makes this the most specific and complete answer among the given options. *Vomiting* - While vomiting is indeed a prominent clinical feature of intestinal obstruction, it can occur in numerous other conditions (gastroenteritis, metabolic disorders, CNS pathology). - **Isolated vomiting lacks specificity** for diagnosing intestinal obstruction. *Fluid level in X-ray > 4* - This refers to **multiple air-fluid levels** seen on erect abdominal X-ray, which is a **radiologic/diagnostic finding**, not a clinical feature. - Clinical features are symptoms and signs (what the patient experiences or what is observed on examination), whereas X-ray findings are **investigative/imaging findings**. *Abdominal distension* - While abdominal distension is a key clinical feature of intestinal obstruction, it can also occur in other conditions (ascites, pregnancy, obesity, bowel perforation). - **Isolated distension lacks specificity** compared to the combination with vomiting.
Question 7: Investigation of choice to diagnose hypertrophic pyloric stenosis in infants is
- A. Gastroscopy
- B. CT scan abdomen
- C. Ultrasound abdomen (Correct Answer)
- D. Contrast radiology
Explanation: ***Ultrasound abdomen*** - **Abdominal ultrasound** is the diagnostic procedure of choice due to its **non-invasive nature**, **lack of radiation exposure**, and high accuracy in visualizing the pylorus. - It allows for direct measurement of the **pyloric muscle wall thickness** (typically >3-4 mm) and **pyloric channel length** (typically >14-17 mm), which are characteristic findings of hypertrophic pyloric stenosis. *Gastroscopy* - While gastroscopy can visualize the gastric outlet, it is an **invasive procedure** and not the primary diagnostic tool due to the risk associated with endoscopy in infants. - It is often reserved for cases where the diagnosis is unclear or other upper gastrointestinal pathologies are suspected. *CT scan abdomen* - **CT scans** expose infants to **ionizing radiation**, making it an unsuitable primary diagnostic investigation, especially when a highly accurate non-irradiating alternative exists. - Although it can show pyloric thickening, its disadvantages outweigh its benefits for this diagnosis. *Contrast radiology* - **Barium studies** are less sensitive and specific than ultrasound for diagnosing pyloric stenosis, especially for distinguishing muscle thickening from spasm. - This method also involves **radiation exposure** and poses a risk of aspiration, making it a secondary choice.
Question 8: Which of the following features is used to identify the colon on an X-ray?
- A. Haustra (Correct Answer)
- B. Valvulae conniventes
- C. String of beads sign
- D. More number of loops
Explanation: ***Haustra (Correct Answer)*** - **Haustra** are sacculations or pouches of the colon created by the uneven contraction of the **taeniae coli** - They are THE characteristic feature that helps distinguish the large bowel from the small bowel on an X-ray - These indentations typically do **not cross the entire width** of the bowel lumen, unlike the valvulae conniventes of the small intestine - Haustra appear as incomplete septations on plain radiographs *Valvulae conniventes (Incorrect)* - **Valvulae conniventes** (also known as plicae circulares) are large, circular folds of the **small intestine** mucosa that project into the lumen - They extend **completely across the lumen** of the small bowel, making them easily distinguishable from haustra which only partially traverse the colon - This is a feature of small bowel, not colon *String of beads sign (Incorrect)* - The "**string of beads sign**" is a **pathological radiographic finding** associated with small bowel obstruction - It refers to multiple small, gas-filled loops of small bowel stacked on top of each other, often with small pockets of fluid or air trapped between the folds, resembling beads on a string - This is not a normal anatomical feature used to identify the colon *More number of loops (Incorrect)* - The number of loops is **not a primary distinguishing feature** between the large and small bowel on an X-ray - While the small intestine generally has more convolutions or loops than the colon, this is a **less reliable and specific sign** compared to the presence of haustra - Haustra remain the gold standard feature for colon identification
Question 9: Treatment of choice for a stab injury to the caecum is
- A. Primary repair (Correct Answer)
- B. Transverse colostomy
- C. Sigmoid colostomy
- D. Caecostomy
Explanation: ***Primary repair*** - For most stab injuries to the caecum, **primary repair** is the treatment of choice, especially when the injury is small and there is no significant tissue loss or contamination. - The caecum has a relatively **large diameter** and **rich blood supply**, which facilitates successful primary closure. - Primary repair is simple, effective, and avoids the morbidity associated with ostomy creation. *Caecostomy* - A **caecostomy** involves bringing a portion of the caecum to the surface as a temporary fecal diversion. - It is generally reserved for more complex injuries with significant tissue loss, severe contamination, or hemodynamic instability requiring damage control surgery. - This procedure carries risks of **infection** and **fistula formation**, and is more invasive than primary repair for isolated stab injuries. *Transverse colostomy* - A **transverse colostomy** is a diverting ostomy created in the transverse colon. - It is typically used for injuries to the distal colon or rectum, or in cases of severe abdominal contamination requiring fecal diversion from a more compromised section of the bowel. - This is a more extensive procedure than necessary for an isolated low-grade caecal injury and would involve unnecessary diversion of a longer segment of colon. *Sigmoid colostomy* - A **sigmoid colostomy** is a diverting ostomy created in the sigmoid colon. - It is primarily indicated for injuries or diseases affecting the distal colon or rectum, providing fecal diversion to allow healing of those structures. - This option is inappropriate for a caecal injury as it is too distal and would not directly protect the site of injury or provide adequate proximal diversion.
Question 10: Most common cause of acute intestinal obstruction in children is
- A. Inguinal hernia
- B. Intussusception (Correct Answer)
- C. Volvulus
- D. None of the options
Explanation: ***Intussusception*** - **Intussusception** is the most common cause of **acute intestinal obstruction** in children, particularly between 3 months and 3 years of age. - It occurs when a segment of the intestine telescopes into an adjacent segment, leading to obstruction and potentially **ischemia**. *Inguinal hernia* - While an **incarcerated inguinal hernia** can cause intestinal obstruction, it is less common than intussusception as the primary cause of acute obstruction in children generally. - It is more frequent in **neonates and infants** but overall incidence of obstruction is lower than intussusception. *Volvulus* - **Volvulus** refers to a twisting of the intestine on its mesentery, often associated with **malrotation**, leading to obstruction and vascular compromise. - While a serious cause of obstruction, especially in neonates, it is less common overall than intussusception in the pediatric population. *None of the options* - This option is incorrect because **intussusception** is a recognized and frequent cause of acute intestinal obstruction in children.
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